The assumption that art (making images) was once decorative and is now communicative of social and political ideas is not accurate. Art has not gone through a lineal process from simple to complex.
Human's have always made images for many reasons: decorative and communicative , emotional, etc. Human beings must communicate to each other.
What some people call making art (drawing, painting, etc. ) is a 'subset' of making images. We use images for a wide spectrum of purposes mainly because we have eyes to see. Humans must communicate with each other. Express their thoughts and reactions.
Art uses visual shapes/forms, colours, lines, to create meaning. Sometimes these 'meanings' are shallow..that is, the image is lacking in conceptual complexity.
Humans vary in the meanings that they are able to attribute to these forms..all depends on what humans know about them.
Art has not moved from decorative to 'communicative' This in not 'recent'.
Humans have used always used their abilities to create images for social engagement and political motives from the beginning of their existence. Some people just call that activity art.
Making images were never used solely for decorative purposes. Making images were also used to communicate ideas.
After all, what is writing?
Writing are small often beautiful shapes that are designed to codify meaning.
The more beautiful examples of writing is called calligraphy.
Before humans taught themselves how to read, they used images to tell themselves stories, to teach their histories, to teach the past.
Nor do I think one 'has to be educated' to appreciate art.
Art is not merely an appreciation of form and content coupled to a sense of esthetics.
Human beings have been creating visual things from the times that they began to draw. What these images mean depend on the context in which image is created, for what purpose it is created, by whom it is created, and for whom it is created.
Human beings associate various levels of meaning with some shapes...Letters and symbols are smaller examples of this process.
